Public water system · IL3116970
ActiveOld Willow Complex
At a glance
Old Willow Complex (PWSID IL3116970) is an active transient non-community water system in Cook County, Illinois. It reports serving 520 people through 16 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 4 violations for this system; none is health-based, and the most recent began in January 2019.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
520
Service connections
16
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Old Willow Complex compare with other water systems in Cook County?
By EPA's size categories, Old Willow Complex is a small system (501 to 3,300 people). Cook County has 251 active public water systems. Its population served is well below the county average of 20,993 people per system, and accounts for less than 0.1% of the 5,269,212 people reported by systems filed under the county. Across Illinois, the 3,872 active systems average 3,204 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Old Willow Complex is about 3.6 times that figure.
What does “transient non-community water system” mean?
A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. Illinois has 1,703 active transient non-community water systems, 44% of the state's 3,872 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 2,808 Illinois systems (73%) list groundwater as their primary source.
Who owns and regulates Old Willow Complex?
EPA lists Old Willow Complex as privately owned. The IL state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 108 of the 251 active systems in Cook County (43%) are also privately owned.
Does Old Willow Complex have drinking water violations?
EPA's records list 4 violations for this system; none is health-based, and the most recent began in January 2019. The violations listed here began between October 1998 and January 2019. By type: 4 monitoring and reporting. The contaminant or rule involved most often is Nitrate (2 of them). EPA lists 3 as resolved and 1 as archived. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2019-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitritecode 1041 | No | Resolved |
| 1998-10-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
All 4 violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Old Willow Complex: frequently asked questions
Who runs Old Willow Complex?
Old Willow Complex (PWSID IL3116970) is a transient non-community water system privately owned. It is regulated by the IL state drinking water program.
How many people does Old Willow Complex serve?
Old Willow Complex reports serving 520 people through 16 service connections in Cook County, Illinois.
Where does Old Willow Complex get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Old Willow Complex have any drinking water violations?
EPA's records list 4 violations for this system; none is health-based, and the most recent began in January 2019. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Old Willow Complex's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. EPA's records list 4 violations for this system; none is health-based, and the most recent began in January 2019. For current results, consult EPA ECHO, or the IL state drinking water program.
Where can I find Old Willow Complex's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Old Willow Complex is a transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
Other water systems in Cook County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Chicago | Cook | 2,721,308 | Community | Surface water |
| Cicero | Cook | 83,000 | Community | Purchased surface water |
| Schaumburg | Cook | 75,750 | Community | Purchased surface water |
| Evanston | Cook | 74,486 | Community | Surface water |
| Arlington Heights | Cook | 73,320 | Community | Purchased surface water |
| Palatine | Cook | 70,875 | Community | Purchased surface water |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Old Willow Complex, PWSID IL3116970, Illinois”, https://aquacensus.com/water-systems/illinois/old-willow-complex-il3116970 (data as of October 1, 2026).